1. Keepalived的安装 1.1. yum install方式 1 yum install -y keepalived
1.2. 安装包编译方式 更多安装包参考:http://www.keepalived.org/download.html
1 2 3 4 5 wget http://www.keepalived.org/software/keepalived-2.0.7.tar.gz tar zxvf keepalived-2.0.7.tar.gz cd keepalived-2.0.7./configure --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --mandir=/usr/share make && make install
2. 常用配置 keepalived配置文件路径:/etc/keepalived/keepalived
。
2.1. MASTER(主机配置) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 global_defs { router_id proxy-keepalived } vrrp_script check_nginx { script "/etc/keepalived/scripts/check_nginx.sh" interval 3 weight 2 } vrrp_instance VI_1 { state BACKUP interface eth2 virtual_router_id 15 priority 100 advert_int 1 authentication { auth_type PASS auth_pass xxx } track_script { check_nginx } virtual_ipaddress { 180.101.115.139 218.98.38.29 } nopreempt notify_master "/etc/keepalived/keepalived_notify.sh master" notify_backup "/etc/keepalived/keepalived_notify.sh backup" notify_fault "/etc/keepalived/keepalived_notify.sh fault" notify_stop "/etc/keepalived/keepalived_notify.sh stop" }
2.2. BACKUP(备机配置) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 global_defs { router_id proxy-keepalived } vrrp_script check_nginx { script "/etc/keepalived/scripts/check_nginx.sh" interval 3 weight 2 } vrrp_instance VI_1 { state BACKUP interface eth2 virtual_router_id 15 priority 99 advert_int 1 authentication { auth_type PASS auth_pass xxx } track_script { check_nginx } virtual_ipaddress { 180.101.115.139 218.98.38.29 } nopreempt notify_master "/etc/keepalived/keepalived_notify.sh master" notify_backup "/etc/keepalived/keepalived_notify.sh backup" notify_fault "/etc/keepalived/keepalived_notify.sh fault" notify_stop "/etc/keepalived/keepalived_notify.sh stop" }
3. 注意事项 1、指定Nginx健康检测脚本:/etc/keepalived/scripts/check_nginx.sh
2、主备配置差别主要为(建议这么配置):
以下两种方式的配置,当其中一台机器keepalived挂掉后会自动VIP切到另一台机器,当挂掉机器keepalived恢复后不会抢占VIP,该方式可以避免机器恢复再次切VIP所带来的影响。
3、指定VIP
1 2 3 4 virtual_ipaddress { 180.101.115.139 218.98.38.29 }
4、可以指定为非抢占:nopreempt,即priority高不会抢占已经绑定VIP的机器。
5、制定绑定IP的网卡: interface eth2
6、可以指定keepalived状态变化通知
1 2 3 4 notify_master "/etc/keepalived/keepalived_notify.sh master" notify_backup "/etc/keepalived/keepalived_notify.sh backup" notify_fault "/etc/keepalived/keepalived_notify.sh fault" notify_stop "/etc/keepalived/keepalived_notify.sh stop"
7、virtual_router_id 15值,主备值一致,但建议不应与集群中其他Nginx机器上的相同,如果同一个网段配置的virtual_router_id 重复则会报错,选择一个不重复的0~255之间的值,可以用以下命令查看已存在的vrid。
1 tcpdump -nn -i any net 224.0.0.0/8
4. 常用脚本 4.1. Nginx健康检测脚本 在Nginx配置目录下(/etc/nginx/conf.d/)增加health.conf的配置文件,该配置文件用于配置Nginx health的接口。
1 2 3 4 5 6 server { listen 80 default_server; server_name localhost; default_type text/html; return 200 'Health'; }
Nginx健康检测脚本:/etc/keepalived/scripts/check_nginx.sh
4.1.1. 检查接口调用是否为200 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 # !/bin/sh set -x timeout=30 #指定默认30秒没返回200则为非健康,该值可根据实际调整 if [ -n ${timeout} ];then httpcode=`curl -sL -w %{http_code} -m ${timeout} http://localhost -o /dev/null` else httpcode=`curl -sL -w %{http_code} http://localhost -o /dev/null` fi if [ ${httpcode} -ne 200 ];then echo `date`': nginx is not healthy, return http_code is '${httpcode} >> /etc/keeperalived/keepalived.log killall keepalived exit 1 else exit 0 fi
4.1.2. 检查Nginx进程是否运行 1 2 3 4 5 # !/bin/sh if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then echo "$(date) nginx pid not found">>/etc/keepalived/keepalived.log killall keepalived fi
4.2. Keepalived状态通知脚本 1 2 3 4 5 6 7 8 # !/bin/bash set -x warn_receiver=$1 ip=$(ifconfig bond0|grep inet |awk '{print $2}') warningInfo="${ip}_keepalived_changed_status_to_$1" warn-report --user admin --key=xxxx --target=${warn_receiver} ${warningInfo} echo $(date) $1 >> /etc/keepalived/status
说明:
ip获取本机IP,本例中IP获取是bond0的IP,不同机器网卡名称不同需要修改为对应网卡名称。
告警工具根据自己指定。